Compared to silicon (Si), silicon carbide (SiC) has excellent properties such as 3 times the bandgap, about 10 times the breakdown electric field strength, and about 3 times the thermal conductivity. A device having low loss and high field effect mobility (channel mobility) is realized by the application of SiC in a semiconductor device such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), etc. It is desirable to further improve the field effect mobility of the semiconductor device.